Question 1

In MS-DOS environments, what is the role of MSCDEX.EXE during system operation?

Accepted Answer

Introduction / Context: Legacy DOS systems required separate drivers to support devices. CD-ROM drives, in particular, needed a pair of drivers: a low-level hardware driver loaded in CONFIG.SYS and a higher-level redirector to provide access via drive letters. MSCDEX.EXE is central to this setup in classic DOS configurations. Given Data / Assumptions: DOS does not natively support ISO-9660 without add-on software. CD-ROM access under DOS typically involves MSCDEX plus a device-specific driver. The question focuses on MSCDEX.EXE specifically. Concept / Approach: MSCDEX (Microsoft CD-ROM Extensions) is a DOS program that enables CD-ROM file system access by interfacing with the low-level device driver and mapping the CD as a DOS drive letter (e.g., D:). It is not a SCSI driver (though many CD-ROMs used SCSI or ATAPI), nor does it configure hard disks or the BIOS. Step-by-Step Solution: Recognize MSCDEX as the CD-ROM Extensions utility for DOS.Understand that it cooperates with a device driver (e.g., OAKCDROM.SYS) loaded in CONFIG.SYS.Identify that its purpose is CD-ROM file system support in DOS.Select 'it's a CD-ROM DOS driver' as the best description among the options. Verification / Alternative check: Historical DOS manuals and setup guides show AUTOEXEC.BAT invoking MSCDEX to assign drive letters for CD-ROMs. Why Other Options Are Wrong: Configures hard drives: handled by DOS/BIOS and partition utilities, not MSCDEX. SCSI driver: MSCDEX is not a hardware driver; it is a redirector. BIOS setup: unrelated. Common Pitfalls: Confusing the low-level CD-ROM device driver with MSCDEX; both are needed, but they serve different roles. Final Answer: it's a CD-ROM DOS driver.

Question 2

In DOS-era terminology, what does the acronym TSR stand for with respect to small utilities that remain active after execution?

Accepted Answer

Introduction / Context: TSR programs were a hallmark of DOS environments. They allowed small utilities (such as pop-up calculators, key enhancers, or clipboard tools) to remain in memory after execution and be invoked later via hotkeys, despite DOS being a single-tasking OS. Given Data / Assumptions: Acronym expansion is requested. DOS memory model and interrupt-driven activation are implied. TSRs hooked interrupts (keyboard/timer) to trigger functionality on demand. Concept / Approach: TSR stands for 'Terminate and Stay Resident' (commonly written without 'and' in informal abbreviations), meaning the program terminates normally to DOS but leaves a portion resident in RAM, ready to resume service when triggered. This provided pseudo-multitasking for simple utilities without a full multitasking kernel. Step-by-Step Solution: Expand the acronym based on historical DOS usage.Match to the option 'Terminate Stay Resident' (the closest standard phrasing in the choices).Confirm that alternatives do not reflect established terminology.Select the correct expansion. Verification / Alternative check: DOS development references and interrupt lists document TSR mechanics and memory footprints extensively, using the phrase 'Terminate and Stay Resident'. Why Other Options Are Wrong: Other expansions are invented and not used historically. None of the above is incorrect because a correct expansion is present. Common Pitfalls: Assuming TSRs provide full multitasking; they only offer limited resident functionality. Final Answer: Terminate Stay Resident.

Question 3

In MS-DOS, which command-line utility quickly displays how much conventional/extended memory is available and in use?

Accepted Answer

Introduction / Context: Diagnosing memory usage in DOS often requires a snapshot of conventional, upper, extended (XMS), and expanded (EMS) memory. Microsoft provided a small utility to summarize this information and list memory-resident drivers and programs. Given Data / Assumptions: The question asks for the quickest command to view available memory. We are in a DOS/command-line setting. Utilities like CHKDSK focus on disks; MEMMAKER tunes memory but does not simply report it. Concept / Approach: The MEM command reports memory usage, including free and used amounts and details on drivers and TSRs when invoked with switches (e.g., MEM /C). It is the standard tool for a quick memory availability check in DOS. Step-by-Step Solution: Identify utilities and their primary purposes.Match 'show memory' requirement to MEM.Exclude disk (CHKDSK) and optimizer (MEMMAKER) tools.Select 'MEM' as correct. Verification / Alternative check: DOS help (MEM /?) confirms it displays the amount of used and free memory. Why Other Options Are Wrong: EMM: not a DOS command; often refers to expanded memory managers (e.g., EMM386), not a reporting tool. CHKDSK: checks disks, not memory usage. MEMMAKER: attempts to optimize memory layout, not merely display it. Common Pitfalls: Using MEMMAKER in place of MEM when only a quick report is needed. Final Answer: MEM.

Question 4

In DOS configuration files, which file typically contains the BUFFERS= statement used to set disk buffer counts?

Accepted Answer

Introduction / Context: DOS boots using two key configuration files: CONFIG.SYS and AUTOEXEC.BAT. Understanding which settings belong in which file is vital for legacy system setup, driver loading, and performance tuning (e.g., disk buffers and device drivers). Given Data / Assumptions: BUFFERS= sets the number of disk buffers that DOS maintains. CONFIG.SYS is parsed by the DOS kernel during boot before AUTOEXEC.BAT. Other filenames in options are either unrelated or from other systems. Concept / Approach: System-level settings and device drivers (HIMEM.SYS, EMM386.EXE, BUFFERS=, FILES=) reside in CONFIG.SYS. AUTOEXEC.BAT typically sets environment variables and launches TSRs/utilities. Therefore, BUFFERS= belongs in CONFIG.SYS. Step-by-Step Solution: Identify BUFFERS= as a kernel configuration directive.Recall DOS boot order and roles of CONFIG.SYS vs. AUTOEXEC.BAT.Eliminate unrelated filenames.Choose 'Config.sys'. Verification / Alternative check: DOS manuals list BUFFERS= under CONFIG.SYS directives alongside FILES= and LASTDRIVE=. Why Other Options Are Wrong: Autoexec.bat: used for commands after kernel initialization, not kernel directives. Other filenames are not DOS boot files. Common Pitfalls: Confusing device driver (.SYS) loading (CONFIG.SYS) with TSR launching (AUTOEXEC.BAT). Final Answer: Config.sys.

Question 5

In MS-DOS, which command or option suppresses the confirmation prompt when deleting a directory and its contents?

Accepted Answer

Introduction / Context: Deleting directories in DOS often requires care to avoid accidental data loss. The DELTREE command removes a directory tree, and DOS normally asks for confirmation. There is a specific switch to bypass that prompt, which technicians used in scripts or automated maintenance tasks. Given Data / Assumptions: The goal is to delete a directory without a confirmation prompt. We are constrained to choose among the listed options. Accurate DOS syntax matters: only the correct switch actually suppresses the prompt. Concept / Approach: In DOS, the correct syntax to suppress confirmation is DELTREE /Y . The /Y switch answers "yes" to all prompts automatically. None of the provided options include /Y. DELTREE alone still prompts. DELTREE/F is not a standard switch. DEL . and ERASE . affect files, not directories recursively, and still may prompt depending on settings. Step-by-Step Solution: Recall the correct syntax: DELTREE /Y.Compare to listed options and note the absence of /Y.Confirm that none of the options suppress the prompt as required.Select 'None of the above' as the only accurate choice. Verification / Alternative check: Microsoft DOS reference confirms /Y as the non-interactive switch for DELTREE. No official /F switch exists for this command in standard MS-DOS. Why Other Options Are Wrong: DELTREE: prompts for confirmation. DELTREE/F: invalid switch and still would not suppress confirmation. DEL.* / ERASE .: do not remove directories recursively and may still prompt. Common Pitfalls: Assuming any switch (like /F) applies; DOS command switches vary by command. Final Answer: None of the above.

Question 6

In MS-DOS, batch files are scripts that run a sequence of commands automatically. Which filename extension identifies a batch file?

Accepted Answer

Introduction / Context: Batch files provide automation in DOS by executing a list of commands in order. They are frequently used to set environment variables, launch programs, or perform maintenance tasks during boot or login. Recognizing their file extension is fundamental for DOS administration and scripting. Given Data / Assumptions: We are identifying the standard file extension for batch scripts in DOS. Other common DOS extensions include .COM (command binaries), .EXE (executables), and .SYS (device drivers). Concept / Approach: By convention, DOS batch scripts use the .BAT extension (e.g., AUTOEXEC.BAT). When executed, the command processor (COMMAND.COM) reads and runs commands from the file sequentially. This is distinct from compiled programs (.EXE, .COM) and system drivers (.SYS). Step-by-Step Solution: List common DOS extensions and their roles.Recall that scripts are .BAT.Eliminate non-script extensions.Select 'BAT' as correct. Verification / Alternative check: Any DOS reference or system files on boot disks (e.g., AUTOEXEC.BAT) confirm this association. Why Other Options Are Wrong: .COM/.EXE: compiled executables, not batch scripts. .SYS: device/system driver files loaded typically in CONFIG.SYS. Common Pitfalls: Confusing AUTOEXEC.BAT (batch) with CONFIG.SYS (configuration directives). Final Answer: BAT.

Question 7

In classic MS-DOS troubleshooting, which built-in diagnostic utility would you run to view detected serial (COM) ports and other system details?

Accepted Answer

Introduction / Context: When diagnosing legacy PCs running MS-DOS, technicians often need to verify which serial (COM) ports the system hardware and BIOS report. MS-DOS provided a small diagnostic program that enumerates hardware, memory, IRQs, and ports, which is especially useful before installing serial-dependent devices like modems or mice. Given Data / Assumptions: Environment: MS-DOS (for example, MS-DOS 5.x or 6.x). Goal: Identify detected serial ports (COM1, COM2, etc.). Preference: A native DOS utility requiring no third-party tools. Concept / Approach: The Microsoft Diagnostics utility, invoked as MSD, displays a menu-driven report including CPU details, memory map, video, IRQ/DMA assignments, and I/O ports. Under the I/O or System Information sections, it lists COM and LPT ports detected via BIOS data structures and direct probing, making it the correct built-in choice for serial port discovery. Step-by-Step Solution: 1) Boot to DOS and navigate to the directory containing MSD (commonly C:\DOS).2) Run: MSD and press Enter.3) Open the I/O Ports or System menu to view COM1/COM2 presence and base addresses (for example, 3F8h, 2F8h).4) Use the information to configure software (for example, selecting COM1 at 3F8h, IRQ4). Verification / Alternative check: Cross-check MSD’s report with CONFIG.SYS, AUTOEXEC.BAT, or device manager utilities to confirm consistency. Testing a serial mouse or modem on the listed port further verifies functionality. Why Other Options Are Wrong: command.com: The command interpreter, not a diagnostic tool. SDET / serial.chk / comdiag: Not standard MS-DOS utilities for port enumeration. Common Pitfalls: Assuming the presence of a COM port guarantees a working device; cabling, IRQ conflicts, or disabled BIOS ports can still block operation. Final Answer: MSD

Question 8

In DOS FDISK workflow, if you must completely wipe a drive (virus recovery) by deleting all DOS partitions, in which correct order should you delete them?

Accepted Answer

Introduction / Context: FDISK in DOS manages Primary and Extended partitions. An Extended partition is a container that holds one or more Logical drives. To fully remove every partition cleanly (for example, after a severe infection), you must respect the containment hierarchy when deleting. Given Data / Assumptions: Disk has a Primary DOS partition and possibly an Extended DOS partition. The Extended DOS partition may contain one or more Logical drives. Goal is a complete wipe via FDISK delete operations before re-creating partitions. Concept / Approach: Because Logical drives live inside the Extended DOS partition, you cannot delete the Extended container while any Logical drives still exist. Therefore, delete Logical drives first, then delete the Extended DOS partition, and finally delete the Primary DOS partition. This order respects dependency and prevents FDISK errors. Step-by-Step Solution: 1) In FDISK, choose “Delete Logical DOS Drive(s) in the Extended DOS Partition”.2) After all Logical drives are removed, choose “Delete Extended DOS Partition”.3) Lastly, choose “Delete Primary DOS Partition”.4) Reboot and re-run FDISK to create fresh partitions, then FORMAT as needed. Verification / Alternative check: FDISK will not allow deleting the Extended partition if any Logical drives remain, confirming the required order. Why Other Options Are Wrong: Primary, Extended, Logical / Extended before Logical: Violate containment; FDISK blocks these operations. Logical, Primary, Extended: Leaves Extended orphaned; invalid order. None of the above: Incorrect because the correct dependency order is known. Common Pitfalls: Forgetting hidden recovery partitions or non-DOS partitions; use appropriate tools to remove them if present. Final Answer: Logical, Extended, Primary

Question 9

In MS-DOS command usage, which command lists all files in the current working directory without switching folders?

Accepted Answer

Introduction / Context: Basic file management in MS-DOS begins with enumerating files in the current directory. The standard, built-in command to display filenames, sizes, dates, and attributes is short, widely known, and available immediately after boot in most DOS versions. Given Data / Assumptions: Current directory is set (for example, C:\DATA). User wants a non-destructive view of file listings. No third-party shell extensions are assumed. Concept / Approach: The DIR command reads directory entries and prints a formatted list. Optional switches (for example, /P for paging, /W for wide format, /O for sort order) control display but the base command already provides a listing of files in the current directory. Step-by-Step Solution: 1) At the prompt, type: DIR and press Enter.2) Use DIR /P if the list is long and scrolls off screen.3) To include hidden/system files, add switches supported by your DOS version.4) Confirm output shows names and summary totals (files, bytes free). Verification / Alternative check: Cross-check with DIR *.EXT to filter by extension; the match confirms the command genuinely lists directory entries. Why Other Options Are Wrong: LIST ALL / SHOW / SHOW ME: Not standard DOS commands. None of the above: Incorrect because DIR is correct. Common Pitfalls: Confusing DIR with TYPE (which prints file contents) or COPY (which duplicates files). Final Answer: DIR

Question 10

In DOS terminology, restarting the operating system without turning system power off is referred to as what type of boot?

Accepted Answer

Introduction / Context: Boot terminology distinguishes between restarts that cycle power and those that do not. In DOS-era PCs, technicians commonly initiated a non-power-cycle restart to recover from software issues without completely resetting the hardware environment. Given Data / Assumptions: System remains powered; only the OS and software state are reinitialized. Common triggers include Ctrl+Alt+Del or issuing a reboot command. Hardware is not fully power-cycled. Concept / Approach: A warm boot restarts the system without removing power, reinitializing software and many hardware registers but typically leaving power on to components. A cold boot, by contrast, follows a complete power cycle or hard reset. DOS documentation and technician jargon consistently label the former as a warm boot. Step-by-Step Solution: 1) Identify whether power remains on during restart.2) If yes, classify as warm boot (software-initiated restart).3) If power is cut and reapplied, classify as cold boot.4) Apply the term consistently in troubleshooting notes and user instructions. Verification / Alternative check: Using Ctrl+Alt+Del on DOS reboots without powering off, confirming “warm boot” behavior. Why Other Options Are Wrong: reboot: Generic term that does not specify warm vs cold. shutdown / system up: Do not denote this specific restart type in DOS jargon. None of the above: Incorrect because warm is the precise term. Common Pitfalls: Assuming all reboots are the same; documentation often requires distinguishing warm from cold for hardware initialization issues. Final Answer: warm

Question 11

In MS-DOS file management, which command creates a new directory (folder) at the specified path?

Accepted Answer

Introduction / Context: Organizing files in DOS requires creating directories to group related documents and programs. DOS provides a concise command to create a directory, with an equivalent long form for users who prefer explicit names. Given Data / Assumptions: User has write permissions to the target path. Path may be absolute (for example, C:\DATA) or relative. No conflicting file or directory name exists at the destination. Concept / Approach: The MD command (alias MKDIR) creates a new directory entry in the filesystem. If intermediate directories do not exist, classic DOS requires creating them one level at a time. The DIR command lists contents; it does not create folders. MAKE and DD are not standard DOS commands for directory creation. Step-by-Step Solution: 1) To create C:\WORK, type: MD C:\WORK and press Enter.2) Verify with DIR C:\ to confirm the new directory appears.3) Change into it using CD C:\WORK as needed.4) Repeat for subfolders (for example, MD C:\WORK\LOGS). Verification / Alternative check: Attempting to run MKDIR C:\WORK performs the same action, demonstrating the MD/MKDIR equivalence. Why Other Options Are Wrong: DIR: Displays contents only. MAKE / DD: Not DOS directory-creation commands. None of the above: Incorrect because MD is correct. Common Pitfalls: Including trailing spaces or reserved device names (for example, PRN) that can cause errors. Final Answer: MD

Question 12

In DOS navigation, which single command takes you directly to the root of the current drive from any subdirectory?

Accepted Answer

Introduction / Context: Efficient command-line navigation requires knowing how to jump to key locations quickly. In DOS, returning to the root directory of the current drive is a frequent operation when resetting paths or launching programs from top-level folders. Given Data / Assumptions: Current drive may be, for example, C: or D:. User is nested within one or more subdirectories. Goal: Return to the root in a single command. Concept / Approach: The CD (change directory) command accepts a backslash as a special path meaning the root of the current drive. Therefore, CD\ instantly moves you to, for example, C:\ regardless of how deep you are. CD.. moves only one level up; CD \root refers to a literal directory named root, which may not exist; CD\.. is a malformed combination for this purpose. Step-by-Step Solution: 1) At any depth, type: CD\ and press Enter.2) Confirm the prompt changes to show the root path (for example, C:\>).3) Optionally navigate back down with CD subfolder names.4) Use DIR to verify top-level directories if needed. Verification / Alternative check: Issuing CD.. repeatedly will eventually reach the root, but CD\ performs it in a single step. Why Other Options Are Wrong: CD \root: Goes to a directory named root if it exists, not necessarily the drive root. CD..: Moves up one level only. CD\..: Not the correct syntax for root navigation. None of the above: Incorrect because CD\ is correct. Common Pitfalls: Confusing the backslash role in DOS (root separator) with forward slashes used for options in some commands. Final Answer: CD\

Question 13

In MS-DOS, you want to display the contents of C:\AUTOEXEC.BAT but the output scrolls too fast. Which correct command paginates the output one screen at a time?

Accepted Answer

Introduction / Context: Large text files printed to the screen with TYPE can scroll past the visible buffer. Piping output through a pager is a standard console technique to read content screen by screen, improving readability without editing the file. Given Data / Assumptions: The file C:\AUTOEXEC.BAT exists and is readable. MS-DOS shell supports pipes and the MORE filter. User wants interactive pagination. Concept / Approach: The pipe character (|) connects the output of one command to the input of another. In DOS, piping TYPE into MORE paginates text by waiting for a keypress at each screenful. Slashes like /P are not valid for TYPE pagination (they are used by other commands), and adding stray punctuation (like a trailing dot) breaks the command. Step-by-Step Solution: 1) Run: TYPE C:\AUTOEXEC.BAT | MORE2) Read the first screen of text; press a key to continue.3) Repeat until the end of file.4) Optionally redirect to a file or printer instead of paging if required. Verification / Alternative check: Try TYPE C:\AUTOEXEC.BAT alone and observe rapid scrolling; then compare with the piped command to confirm pagination works. Why Other Options Are Wrong: TYPE ... /P or /MORE: TYPE does not support these switches for paging. TYPE ... | PAUSE: Pauses once, not paginated viewing. TYPE ... | MORE.: Trailing dot invalidates the pager command. Common Pitfalls: Forgetting the space before and after the pipe or mis-typing the path, which leads to “File not found.” Final Answer: TYPE C:\AUTOEXEC.BAT | MORE

Question 14

Which MS-DOS XCOPY syntax copies only files with a timestamp on or after the specified date (that is, modified since a given date)?

Accepted Answer

Introduction / Context: Incremental file maintenance often requires copying only files that have changed since a particular date. MS-DOS provides an extended copy command that supports date-based filtering to streamline backups and deployments without redundantly copying unchanged files. Given Data / Assumptions: XCOPY is available (commonly in C:\DOS). User supplies a date parameter appropriate to the DOS locale (for example, mm-dd-yy). Goal: Copy files modified on or after the specified date. Concept / Approach: The XCOPY /D:date switch selects files whose last-write time is on or after the provided date. XCOPY then copies only those qualifying files to the target. COPY does not support /D:date. Other switches like /V verify copies but do not filter by date. COPY /M is not a DOS standard for date-based selection. Step-by-Step Solution: 1) Choose a cutoff date, for example, 06-01-25.2) Run: XCOPY C:\SRC\. D:\DEST\ /D:06-01-253) XCOPY scans timestamps and selects only newer or same-day files.4) Review summary to confirm the number of files copied. Verification / Alternative check: Re-run the same command immediately; with no newer files, XCOPY should report zero files copied, confirming date filtering. Why Other Options Are Wrong: COPY /D:date and COPY /M: COPY lacks these date-based semantics. XCOPY /V: Verifies data after copy; does not filter by date. None of the above: Incorrect since XCOPY /D:date is valid. Common Pitfalls: Using the wrong date format for the configured locale, leading to unintended selections, or forgetting to include subdirectories with XCOPY switches like /S if needed. Final Answer: XCOPY /D:date

Question 15

With respect to MS-DOS architecture, which statement correctly describes external DOS commands compared to internal commands?

Accepted Answer

Introduction / Context: DOS distinguishes internal commands (built into the shell, typically COMMAND.COM) from external commands (standalone .COM/.EXE utilities stored on disk). Recognizing this difference explains why some commands work even if the PATH is altered or media are missing, while others fail until their files are located. Given Data / Assumptions: Internal commands load with the command interpreter. External commands are separate executables (for example, XCOPY.EXE, FORMAT.COM). Execution depends on the file being found via PATH or explicit path. Concept / Approach: Because external commands are not part of COMMAND.COM, they remain on disk and are loaded into RAM only when invoked. If the executable is unavailable or not on the PATH, the command will not run. Internal commands, by contrast, are always available after boot because they are resident within the shell. Step-by-Step Solution: 1) Identify the command type (internal vs external).2) For external commands, ensure the executable file exists and is on the PATH.3) Invoke the command; DOS loads it into memory at runtime.4) On completion, the program exits and RAM is reclaimed. Verification / Alternative check: Remove or rename XCOPY.EXE and note that the XCOPY command fails, proving its external nature; internal commands like DIR continue to work. Why Other Options Are Wrong: Reside in RAM until called: Backwards; they are loaded only when called. Must use /e: No universal /e requirement. Only from batch files: They can run interactively or in batch. Common Pitfalls: Confusing DIR (internal) with external utilities and misconfiguring PATH so external commands are not found. Final Answer: External commands are stored on disk separately from COMMAND.COM

Question 16

In MS-DOS, which command moves a file from one directory to another (optionally renaming it at the destination)?

Accepted Answer

Introduction / Context: Relocating files between directories is a routine administrative task. While copying duplicates data, moving transfers the file to a new path and removes the original, saving space and keeping a single, authoritative copy. Given Data / Assumptions: Source and destination directories exist and are writable. User wants to relocate, not duplicate, the file. MS-DOS MOVE utility is available (included in later DOS versions and Windows DOS boxes). Concept / Approach: The MOVE command changes a file’s directory entry to the target location, performing a rename across paths (and physically copying then deleting if required across volumes). COPY leaves the original in place; RENAME changes the name within the same directory only. CP is a UNIX command, not DOS. Step-by-Step Solution: 1) To move REPORT.TXT from C:\WORK to C:\ARCHIVE, run: MOVE C:\WORK\REPORT.TXT C:\ARCHIVE\2) Verify the file appears in the destination with DIR C:\ARCHIVE3) Confirm it is no longer present in the source directory.4) Optionally rename while moving: MOVE REPORT.TXT ARCHIVE\REPORT_OLD.TXT Verification / Alternative check: Attempting the same operation with RENAME across directories fails, confirming that MOVE is required for cross-directory relocation. Why Other Options Are Wrong: COPY: Duplicates without deleting the source. RENAME: Renames in-place within one directory. CP: Not a DOS command. None of the above: Incorrect because MOVE is correct. Common Pitfalls: Forgetting to include a trailing backslash on the destination directory or omitting quotes when paths contain spaces in later DOS shells. Final Answer: MOVE

Question 17

In legacy MS-DOS environments, which executable must be loaded to enable CD-ROM (ISO-9660) drive access via a DOS drive letter?

Accepted Answer

Introduction / Context: On classic MS-DOS systems, optical drives did not work out of the box. Accessing a CD-ROM required a two-layer driver model: a low-level hardware driver and a high-level redirector that exposed the disc as a DOS drive letter (for example, D:). Knowing which utility performs this role is essential for configuring legacy PCs and understanding boot disks used by technicians and retro-computing enthusiasts. Given Data / Assumptions: We are in an MS-DOS context (not Windows NT/2000+). Objective: enable reading ISO-9660 CDs from DOS using a standard drive letter. Typical CONFIG.SYS and AUTOEXEC.BAT workflow is assumed. Concept / Approach: The standard stack is: load a device-specific CD driver (e.g., OAKCDROM.SYS) in CONFIG.SYS, then load Microsoft CD-ROM Extensions in AUTOEXEC.BAT. The latter, named MSCDEX.EXE, is a redirector that interfaces with the device driver and integrates the CD file system into DOS, assigning a letter and enabling directory/file access. Other executables listed in the options serve unrelated purposes: VLM.EXE is a NetWare client component, CDDEX.EXE is not the Microsoft utility, and DOSKEY.EXE provides command history and macros only. Step-by-Step Solution: Identify that a CD-ROM redirector is needed above the device driver.Recall the filename: MSCDEX.EXE (Microsoft CD-ROM Extensions).Check options and match the exact utility name.Select MSCDEX.EXE as the correct answer. Verification / Alternative check: Typical AUTOEXEC.BAT lines include: MSCDEX /D:MSCD001 /L:D which confirms the required component and its parameters (/D device name, /L drive letter). Why Other Options Are Wrong: VLM.EXE: NetWare DOS requester module, unrelated to CD-ROM file systems. CDDEX.EXE: nonstandard name; the Microsoft tool is MSCDEX. DOSKEY.EXE: keyboard macro/history helper, no file-system function. None of the above: incorrect because MSCDEX.EXE is present. Common Pitfalls: Confusing the low-level device driver (.SYS) with MSCDEX; both are needed for full functionality. Assuming Windows 9x native support applies equally to pure DOS mode—DOS still needs MSCDEX. Final Answer: MSCDEX.EXE.

Question 18

In MS-DOS maintenance, which command detects, diagnoses, and repairs logical and physical disk errors on both uncompressed and DoubleSpace-compressed drives?

Accepted Answer

Introduction / Context: Preventive maintenance on MS-DOS systems relied on utilities that verified and repaired disks. Understanding which tool checks file system integrity, surface conditions, and supports DoubleSpace-compressed volumes is vital for restoring data access and preventing further corruption on legacy PCs. Given Data / Assumptions: We are dealing with DOS 6.x era tools. Target functionality: detect and fix logical errors (FAT, directory) and test for physical issues; must work with DoubleSpace volumes. Commands listed include general maintenance utilities. Concept / Approach: SCANDISK performs file system checks, fixes allocation errors, cross-linked files, lost clusters, and optionally scans the surface for bad sectors. It is also aware of DoubleSpace/DriveSpace compressed volumes. DEFRAG reorganizes files to reduce fragmentation but does not repair logical errors. DBLSPACE manages compression containers; it is not a repair tool. MSAV (Microsoft Anti-Virus) scans for malware, not file system errors. Step-by-Step Solution: List each candidate utility and its core purpose.Match the requirement (detect, diagnose, repair; uncompressed and DoubleSpace) to SCANDISK.Eliminate defragmenter, compression manager, and anti-virus.Select SCANDISK as correct. Verification / Alternative check: Typical usage: SCANDISK C: /SURFACE verifies both logical integrity and physical media, demonstrating its intended role on DOS systems including compressed drives with the proper driver stack loaded. Why Other Options Are Wrong: DEFRAG: only optimizes file placement; no structural repairs. DBLSPACE: creates/manages compressed volumes; not a repair utility. MSAV: anti-virus; unrelated to FAT/dir repairs. None of the above: incorrect because SCANDISK fits exactly. Common Pitfalls: Running DEFRAG on a damaged file system before SCANDISK risks data loss. Ignoring /surface tests when intermittent read errors occur. Final Answer: SCANDISK.

Question 19

In MS-DOS 6.x, which command is used to compress existing disks and create new compressed volumes (DoubleSpace/DriveSpace)?

Accepted Answer

Introduction / Context: Disk compression utilities increased effective storage on small hard drives in the DOS era. Microsoft shipped DoubleSpace (later DriveSpace) to create and manage compressed volumes. Identifying the right command prevents confusion with repair or defragmentation tools and is key to maintaining compressed environments safely. Given Data / Assumptions: Task: compress existing media and create new compressed volumes. We are using stock MS-DOS utilities. Terminology: DoubleSpace (DBLSPACE) and DriveSpace (DRVSPACE) depending on version/licensing. Concept / Approach: DBLSPACE is the command-line front end for configuring DoubleSpace: creating compressed drives, mounting/unmounting, and status queries. DEFRAG reorders files for speed; SCANDISK repairs logical issues; MSAV scans for viruses. Only DBLSPACE directly handles compression container creation and management. Step-by-Step Solution: Review each command's primary function.Match compression tasks with DBLSPACE.Exclude DEFRAG, SCANDISK, MSAV as non-compression tools.Select DBLSPACE. Verification / Alternative check: Usage examples include: DBLSPACE /CREATE to create a compressed volume and DBLSPACE /MOUNT to attach it, confirming the role of the utility. Why Other Options Are Wrong: DEFRAG: no compression, only optimization. SCANDISK: repair, not compression creation. MSAV: anti-virus utility. None of the above: incorrect; DBLSPACE is correct. Common Pitfalls: Compressing a disk with errors; always run SCANDISK first. Confusing DriveSpace (DRVSPACE) in later versions with DoubleSpace naming. Final Answer: DBLSPACE.

Question 20

In MS-DOS command usage, which command removes a directory only if it is empty (contains no files or subdirectories)?

Accepted Answer

Introduction / Context: File and directory management in MS-DOS uses simple commands with specific behaviors. Deleting a directory safely requires knowing which command enforces the “empty only” rule, preventing accidental removal of content. This is especially important when scripting batch operations that manipulate directory trees. Given Data / Assumptions: The directory should be removed only if it is empty. We are operating with standard DOS shell commands. No recursive deletion (like DELTREE) is implied in the question. Concept / Approach: The RD (or RMDIR) command removes an empty directory. If files or subfolders exist, RD fails, protecting contents by default. DEL/ERASE act on files, not directories. MD creates a directory rather than removing it. For recursive deletions, DOS provided DELTREE, but that is outside this question's scope and purposely riskier. Step-by-Step Solution: Identify the command that targets directories specifically.Confirm behavior: succeeds only if directory is empty.Exclude file deletion (DEL/ERASE) and directory creation (MD).Choose RD. Verification / Alternative check: Typing HELP RD or RD /? in DOS explains that RD removes a directory, failing if it contains files. This matches the requirement precisely. Why Other Options Are Wrong: DEL .: deletes files in current directory, not the directory itself. ERASE: synonym for DEL (files only). MD: makes a directory, opposite of the task. None of the above: incorrect because RD is valid and correct. Common Pitfalls: Assuming DEL can delete directories; it cannot unless combined with tools like DELTREE. Attempting RD on nonempty directories, which will fail and require cleaning files first. Final Answer: RD.

Disk Operating System (DOS) Questions